The researchers placed sound monitoring devices at the bedsides of 58 premature infants in the NICU at St. Louis Children’s Hospital. Twenty-five of the babies were in private rooms.

The researchers found that the average noise level was nearly 59 decibels, with peaks of nearly 87 decibels. The study also found that preemies in private rooms, which are increasingly common in NICUs, have much longer periods of silence than those in ward settings. Private rooms can be too quiet in terms of beneficial sounds, especially if parents can’t visit their infants, the researchers said.

“Understanding the NICU auditory environment paves the way for interventions that reduce high levels of adverse sound and enhance positive forms of auditory exposure, such as language,” the authors write.